Generally, I use my 184 10ex's in such conditions. If the snow is rotten to a foot or more, my 190 Explosivs look weird out of powder to most people, but do a fantastic job in deep slop, and are surprisingly tolerant of the harder portions of the mtn. In the other direction, if there is only a couple of inches of slush on top of a harder base, I use my 184 xp100's (123-68-106).
Just to head off any "ski caddy needed" comments, there are definite differences between these skis and how they handle in different conditions, so I have clear and pretty well established preferences. However, all of the above skis are quite usable in any of the conditions mentioned above, so I usually pull one out of the roof-top box in the AM and usually wind up not switching at all during a single day, or maybe only once as much of the mtn goes into shadow in the PM or the weather dramatically changes.
In terms of versatility, I find that my fatter skis tolerate variable conditions better than skinnier skis, so if there is any question, I'll usually err in the direction of going fatter.
I know the above (ie, fatter when its deeper/softer) isn't exactly rocket science, but maybe it will give you a bit of perspective.
Tom / PM
PS (in edit) - I just noticed you also mentioned 75 mm park skis and SL's. I have a pr of 173 Enemies, and while they are also versatile, I prefer them over the others only if just the top couple of inches are soft AND I know I'll be going slow, helping beginners, will be on narrow trails, etc. My 170 9.16's never see the light of day in these conditions.
[ March 13, 2003, 01:20 AM: Message edited by: PhysicsMan ]